Prostate, colon and breast tissues are all associated with a high prevalence of cancer, and are in fact with lung cancer, the most deadly forms of cancer in the United States today.
Prostate cancer is the most prevalent form of cancer in men in the United States. It is anticipated that an estimated 334,500 new cases of prostate cancer will be diagnosed in 1997 (in Cancer Facts and Figures: 1997, American Cancer Society, Atlanta, 1997). The incidence rate for prostate cancer has increased 50% between 1989 and 1993
Early diagnosis is critical for survival, for example, if a tumor is discovered while it is still localized, the 5 year survival rate is 99%. However, early diagnosis at the present time is limited to relatively unreliable methods. These methods include a digital rectal exam and prostate specific antigen (PSA) test. However, digital exam may require that the tumor has become quite large and the cancer may be at a more advanced stage. Ultrasonography has demonstrated that 20% to 30% of cancers detected using this method are not detectable using PSA tests. In addition, false positives are a significant problem as well (in Cancer: Principles and Practice of Oncology, DeVita, Hellman and Rosenberg (eds), J.B. Lippincott Company, Philadephia, pp:538-589, 1993).
Breast cancer is the second major cause of cancer death in women. Approximately 110/100,000 women will be diagnosed with breast cancer each year, and it is expected that in 1997 there will be 43,900 deaths related to breast cancer (in Cancer Facts and Figures: 1997, American Cancer Society, Atlanta, 1997). Early detection is the key to survival and mammograms are generally accepted as the most valuable tool that is available for early detection. Once a tumor is recognizable by physical symptoms the tumor has generally progressed.
An estimated 94,100 cases of colon cancer will be identified in 1997, and 10% of all cancer deaths will be related to colorectal cancer (in Cancer Facts and Figures: 1997, American Cancer Society, Atlanta, 1997). While diagnosis and treatment have been steadily improving, early detection is important for survival. In addition, the cells in these tissues have a high rate of turnover and metabolic activity, and therefore, generally produce a large spectrum of proteins. Included are proteins with secretory functions, and this is particularly common in tissue involved in transporting substances to the outside of the body. One type of substance produced by secretory tissues is anti-microbial agents, in particular antimicrobial proteins. These proteins can act via several mechanisms that include: enzymatic mechanisms, such as, breaking down microbial protective sustances or the microbial cell wall/membrane or the proteins can be very sticky and trap microorganisms. The antimicrobial proteins produced by secretory tissue play an important role in maintaining the body's ability to prevent infection in a more non-specific way than is generally associated with components of the immune system.
Thus, the present invention provides proteins that will be valuable as markers for changes in metabolism highly suspectible to cancerous growth, as well as other uses that should be apparent to those skilled in the art from the teachings herein.